Cancer is currently the second greatest cause of death in the United States behind coronary heart disease. Even though there is trend toward lower death rates from cancer in the U.S., it has been estimated that the annual personal and financial cost of cancer will be $1.62 trillion dollars by 2017. Further, according to the World Health Organization cancer is set to become the leading cause of death world-wide by 2010.
A particularly nefarious cancer is hepatocellular carcinoma (HCC). This is a primary liver cancer as opposed to a secondary or metastatic liver cancer that begins in another organ and migrates to the liver. HCC accounts for 80 to 90% of liver cancers and occurs in men more than women and is usually seen in patients between about 50 and 60 years old. It is more prevalent in Africa and Asia than the Americas and Europe. Its reputation is due not so much to any particular virulence compared to other solid tumor cancers but rather to the fact that it is rarely diagnosed at an early stage of development and when it is discovered, most chemotherapies and radiation treatment are usually ineffective. Surgery is the only recourse but even then it is very difficult to completely remove the entire tumor; the 5-year survival rate for patients with resectable HCCs is 60%, which is low by current standards. For unresectable tumors the prognosis is extremely poor: the disease is usually deadly within 3-6 months of diagnosis.
The currently preferred treatment for unresectable HCC, which is thought to extend the lifespan of a patient to 1-2 years, is transcatheter arterial chemoembolization (TACE). TACE is implemented in two ways. In the first, a drug is administered in a sterile drip into a selected artery servicing the tumor. After the drug has been administered over a period of time, usually about 30 minutes, microparticles such as gelfoam are infused into the artery to cut off the flow of blood to the tumor. In the second procedure, the chemotherapeutic agent itself is loaded onto microbeads which then are infused into the artery where they serve both to block blood flow and to deliver the drug.
The problem is that by either of the above methods the drug concentration reaches a maximum in serum, i.e., blood in the vicinity of the tumor, within about 5 minutes of administration. It then drops to a baseline level within about 24 hours. Because of the variation in the drug concentration, TACE must presently be repeated every 4 to 12 weeks.
What is needed is a method for applying TACE in a manner such that a single application of the procedure lasts for a prolonged period, preferably at least 6 months or more. The current invention provides such a method.